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Hot spot temperature in an HTS Coil: Simulations with MIITs and finite element method

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Hot spot temperature in an HTS Coil : Simulations with MIITs and finite element method. / Härö, E.; Stenvall, A.; Van Nugteren, J.; Kirby, G.

In: IEEE Transactions on Applied Superconductivity, Vol. 25, No. 2, 01.04.2015.

Research output: Contribution to journalArticleScientificpeer-review

Harvard

Härö, E, Stenvall, A, Van Nugteren, J & Kirby, G 2015, 'Hot spot temperature in an HTS Coil: Simulations with MIITs and finite element method', IEEE Transactions on Applied Superconductivity, vol. 25, no. 2. https://doi.org/10.1109/TASC.2015.2396945

APA

Härö, E., Stenvall, A., Van Nugteren, J., & Kirby, G. (2015). Hot spot temperature in an HTS Coil: Simulations with MIITs and finite element method. IEEE Transactions on Applied Superconductivity, 25(2). https://doi.org/10.1109/TASC.2015.2396945

Vancouver

Härö E, Stenvall A, Van Nugteren J, Kirby G. Hot spot temperature in an HTS Coil: Simulations with MIITs and finite element method. IEEE Transactions on Applied Superconductivity. 2015 Apr 1;25(2). https://doi.org/10.1109/TASC.2015.2396945

Author

Härö, E. ; Stenvall, A. ; Van Nugteren, J. ; Kirby, G. / Hot spot temperature in an HTS Coil : Simulations with MIITs and finite element method. In: IEEE Transactions on Applied Superconductivity. 2015 ; Vol. 25, No. 2.

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@article{a195db88b0804c2f8fd9348a824b1e0c,
title = "Hot spot temperature in an HTS Coil: Simulations with MIITs and finite element method",
abstract = "MIITs, a zero-dimensional concept to study hot spot temperature, has been previously used to estimate hot spot temperatures and quench heater delays in NbTi and Nb3Sn magnets. However, quench behavior is completely different in high-temperature superconducting (HTS) magnets due to the slow normal zone propagation velocity and the high temperature margin. Because the MIITs concept does not take into account thermal diffusion in the magnet, opposite to the finite-element method (FEM) analysis, the difference of these concepts is studied in this paper. Here, we have taken the approach to compute the hot spot temperatures for a future HTS magnet, designed to be built from REBCO Roebel cable, with MIITs and FEM simulations. The magnet protection is accomplished with a dump resistor, and the effect of quench detection threshold voltage on the hot spot temperature has been studied. Furthermore, the inductance of the magnet increases with the magnet length. Thus, there exists a maximum inductance of the magnet, which should not be exceeded to be able to protect the magnet only with a dump resistor. The hot spot temperatures with different values of inductance are also studied in this paper. Our simulations show that the hot spot temperatures computed with MIITs are from 60 to 150 K higher than those of FEM analysis. Thus, the MIITs concept seems unreliable when considering hot spot temperatures in HTS magnets protected with only dump resistors. However, the MIITs concept might be a usable tool when comparing different magnet designs. If 400 K is the upper limit for the hot spot temperature and the protection scheme includes only a dump resistor, the length of the investigated magnet can be increased to only such value that the magnet inductance is at most 50 mH.",
keywords = "Finite element method (FEM), high-temperature superconductors (HTSs), quench simulation, stability analysis, superconducting magnets",
author = "E. H{\"a}r{\"o} and A. Stenvall and {Van Nugteren}, J. and G. Kirby",
year = "2015",
month = "4",
day = "1",
doi = "10.1109/TASC.2015.2396945",
language = "English",
volume = "25",
journal = "IEEE Transactions on Applied Superconductivity",
issn = "1051-8223",
publisher = "Institute of Electrical and Electronics Engineers",
number = "2",

}

RIS (suitable for import to EndNote) - Download

TY - JOUR

T1 - Hot spot temperature in an HTS Coil

T2 - Simulations with MIITs and finite element method

AU - Härö, E.

AU - Stenvall, A.

AU - Van Nugteren, J.

AU - Kirby, G.

PY - 2015/4/1

Y1 - 2015/4/1

N2 - MIITs, a zero-dimensional concept to study hot spot temperature, has been previously used to estimate hot spot temperatures and quench heater delays in NbTi and Nb3Sn magnets. However, quench behavior is completely different in high-temperature superconducting (HTS) magnets due to the slow normal zone propagation velocity and the high temperature margin. Because the MIITs concept does not take into account thermal diffusion in the magnet, opposite to the finite-element method (FEM) analysis, the difference of these concepts is studied in this paper. Here, we have taken the approach to compute the hot spot temperatures for a future HTS magnet, designed to be built from REBCO Roebel cable, with MIITs and FEM simulations. The magnet protection is accomplished with a dump resistor, and the effect of quench detection threshold voltage on the hot spot temperature has been studied. Furthermore, the inductance of the magnet increases with the magnet length. Thus, there exists a maximum inductance of the magnet, which should not be exceeded to be able to protect the magnet only with a dump resistor. The hot spot temperatures with different values of inductance are also studied in this paper. Our simulations show that the hot spot temperatures computed with MIITs are from 60 to 150 K higher than those of FEM analysis. Thus, the MIITs concept seems unreliable when considering hot spot temperatures in HTS magnets protected with only dump resistors. However, the MIITs concept might be a usable tool when comparing different magnet designs. If 400 K is the upper limit for the hot spot temperature and the protection scheme includes only a dump resistor, the length of the investigated magnet can be increased to only such value that the magnet inductance is at most 50 mH.

AB - MIITs, a zero-dimensional concept to study hot spot temperature, has been previously used to estimate hot spot temperatures and quench heater delays in NbTi and Nb3Sn magnets. However, quench behavior is completely different in high-temperature superconducting (HTS) magnets due to the slow normal zone propagation velocity and the high temperature margin. Because the MIITs concept does not take into account thermal diffusion in the magnet, opposite to the finite-element method (FEM) analysis, the difference of these concepts is studied in this paper. Here, we have taken the approach to compute the hot spot temperatures for a future HTS magnet, designed to be built from REBCO Roebel cable, with MIITs and FEM simulations. The magnet protection is accomplished with a dump resistor, and the effect of quench detection threshold voltage on the hot spot temperature has been studied. Furthermore, the inductance of the magnet increases with the magnet length. Thus, there exists a maximum inductance of the magnet, which should not be exceeded to be able to protect the magnet only with a dump resistor. The hot spot temperatures with different values of inductance are also studied in this paper. Our simulations show that the hot spot temperatures computed with MIITs are from 60 to 150 K higher than those of FEM analysis. Thus, the MIITs concept seems unreliable when considering hot spot temperatures in HTS magnets protected with only dump resistors. However, the MIITs concept might be a usable tool when comparing different magnet designs. If 400 K is the upper limit for the hot spot temperature and the protection scheme includes only a dump resistor, the length of the investigated magnet can be increased to only such value that the magnet inductance is at most 50 mH.

KW - Finite element method (FEM)

KW - high-temperature superconductors (HTSs)

KW - quench simulation

KW - stability analysis

KW - superconducting magnets

U2 - 10.1109/TASC.2015.2396945

DO - 10.1109/TASC.2015.2396945

M3 - Article

VL - 25

JO - IEEE Transactions on Applied Superconductivity

JF - IEEE Transactions on Applied Superconductivity

SN - 1051-8223

IS - 2

ER -